Alkaloids, mainly tropanes, elaborated by plants of the family Solanaceae, including Atropa, Hyoscyamus, Mandragora, Nicotiana, Solanum, etc. Some act as cholinergic antagonists; most are very toxic; many are used medicinally.

Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)

Alkaloids originally isolated from the ergot fungus Claviceps purpurea (Hypocreaceae). They include compounds that are structurally related to ergoline (ERGOLINES) and ergotamine (ERGOTAMINES). Many of the ergot alkaloids act as alpha-adrenergic antagonists.

Group of alkaloids containing a benzylpyrrole group (derived from TRYPTOPHAN)

A group of ALKALOIDS, characterized by a nitrogen-containing necine, occurring mainly in plants of the BORAGINACEAE; COMPOSITAE; and LEGUMINOSAE plant families. They can be activated in the liver by hydrolysis of the ester and desaturation of the necine base to reactive electrophilic pyrrolic CYTOTOXINS.

A group of indole-indoline dimers which are ALKALOIDS obtained from the VINCA genus of plants. They inhibit polymerization of TUBULIN into MICROTUBULES thus blocking spindle formation and arresting cells in METAPHASE. They are some of the most useful ANTINEOPLASTIC AGENTS.

Alkaloids extracted from various species of Cinchona.

A group of related plant alkaloids that contain the BERBERINE heterocyclic ring structure.

Alkaloids derived from TYRAMINE combined with 3,4-dihydroxybenzaldehyde via a norbelladine pathway, including GALANTAMINE, lycorine and crinine. They are found in the Amaryllidaceae (LILIACEAE) plant family.